Dryopteris erythrosora (autumn fern, Japanese wood fern, copper shield fern) is a species of fern in the family Dryopteridaceae, native to east Asia from China and Japan south to the Philippines, growing in light woodland shade on low mountains or hills. It is semi-evergreen, with bipinnate fronds 30–70 cm (12–28 in) tall by 15–35 cm (6–14 in) broad, with 8-20 pairs of pinnae. The fronds have a coppery tint when young, but mature to dark green.
The Latin specific epithet erythrosora means “having red spore cases”.
D. erythrosora can tolerate a drier soil than many ferns, but is most successful in moist, humus-rich soil, with a pH range of 6.1 to 7.5, with morning or late afternoon sunshine but not during the middle of the day. It is hardy zones 5 to 11. Numerous cultivars have been selected, including ‘Prolifica’ and ‘Viridosora’. Propagation is by division in spring, separating the small crowns from the larger crowns, or by spores.